Printed circuit board assembly, integrated circuit and electronic equipment

Abstract

The invention provides a printed circuit board assembly, an integrated circuit and electronic equipment, the printed circuit board assembly comprises a target printed circuit board and bonding pads, and the bonding pads circumferentially arranged along the boundary of a solder ball array packaging area on the target printed circuit board are first bonding pads or second bonding pads. According to the printed circuit board assembly, the integrated circuit and the electronic equipment provided by the invention, the thermal expansion coefficients of the bonding pads arranged in the peripheral direction of the boundary of the solder ball array packaging area on the target printed circuit board in the printed circuit board assembly are consistent; according to the invention, the condition that the first bonding pad and the second bonding pad are adjacent to each other in the bonding pads circumferentially arranged at the boundary of the solder ball array packaging area on the target printed circuit board is avoided, so that an insulating layer below the bonding pads arranged at the boundary and corners of the solder ball array packaging area on the target printed circuit board is better prevented from being torn; the stability of electrical performance and mechanical strength of the printed circuit board assembly can be improved, and the reliability of the printed circuit board assembly can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of printed circuit boards, and in particular to a printed circuit board assembly, an integrated circuit and an electronic device. Background Art

[0002] Printed Circuit Board Assembly (PCBA) refers to a circuit board assembly formed by soldering electronic components to a printed circuit board (PCB).

[0003] The insulation layer in the PCBA can provide electrical insulation for the PCBA, protect the electronic components on the PCBA, improve the mechanical strength of the PCBA, and optimize the thermal management of the PCBA. However, the insulation layer in the PCBA is easily torn due to stress, design defects, manufacturing process, and environmental factors. The tearing of the insulation layer in the PCBA will cause the PCBA to have problems such as reduced electrical performance, weakened mechanical strength, and reduced reliability.

[0004] Therefore, how to better avoid the tearing of the insulation layer in PCBA is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] The present invention provides a printed circuit board assembly, an integrated circuit and an electronic device, which are used to solve the defects in the prior art that the tearing of the insulation layer in the PCBA will lead to the degradation of the electrical performance, weakening of the mechanical strength and reduction of the reliability of the PCBA, so as to better avoid the tearing of the insulation layer in the PCBA.

[0006] The present invention provides a printed circuit board assembly, comprising: a target printed circuit board and a pad; the pad is arranged on an insulating layer in the target printed circuit board; The pad includes a first pad and / or a second pad; a via is provided below the first pad, an inner wall of the via is covered with a metal layer, and an interior of the metal layer is filled with an insulating material; All the pads arranged along the circumference of the boundary of the solder ball array packaging area on the target printed circuit board are the first pads or the second pads.

[0007] According to a printed circuit board assembly provided by the present invention, the target printed circuit board is obtained by pressing a plate material, a conductive layer and an insulating layer. When pressing the plate material, the conductive layer and the insulating layer, the curing time of the stacked plate material, the conductive layer and the insulating layer under a preset temperature and a preset pressure is a target time. The target time is the sum of an original curing time and a first preset time. The original curing time is determined based on the characteristics of the plate material, the conductive layer and the insulating layer. The value range of the first preset time is between 12 minutes and 18 minutes.

[0008] According to a printed circuit board assembly provided by the present invention, the target printed circuit board is obtained by laminating a plate material, a conductive layer and an insulating layer. When the plate material, the conductive layer and the insulating layer are laminated, the stacked plate material, the conductive layer and the insulating layer are cured at a preset temperature and a preset pressure, and then the obtained multilayer structure is cooled at a cooling rate not greater than a target cooling rate, and the target cooling rate ranges from 0.8°C / minute to 1.2°C / minute.

[0009] According to a printed circuit board assembly provided by the present invention, the first pad includes a first common pad and a first enlarged pad, and the diameter of the first enlarged pad is greater than the diameter of the first common pad; In the case where all the pads arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board are the first pads, the first pads arranged at the corners of the solder ball array packaging area on the target printed circuit board are the first enlarged pads, the remaining first pads arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board are the first common pads, and the target area on the first enlarged pads arranged at the corners of the solder ball array packaging area on the target printed circuit board is covered by solder resist oil, and the target annular area on the first enlarged pad is an area on the outside of the first enlarged pad that is larger than the first common pad; The second pad includes a second common pad and a second enlarged pad, and the diameter of the second enlarged pad is greater than the diameter of the second common pad; In the case where all the pads arranged circumferentially along the boundary of the solder ball array packaging area on the target printed circuit board are the second pads, the second pads arranged at the corners of the solder ball array packaging area on the target printed circuit board are the second enlarged pads, the remaining second pads arranged circumferentially along the boundary of the solder ball array packaging area on the target printed circuit board are the second common pads, and the target area on the second enlarged pads arranged at the corners of the solder ball array packaging area on the target printed circuit board is covered by solder resist, and the target annular area on the second enlarged pad is an area on the outer side of the second enlarged pad that is larger than the second common pad.

[0010] According to a printed circuit board assembly provided by the present invention, the target printed circuit board is obtained by laminating a plate material, a conductive layer and an insulating layer. When laminating the plate material, the conductive layer and the insulating layer, the curing time of the stacked plate material, the conductive layer and the insulating layer at a preset temperature and a preset pressure is a target time. After the stacked plate material, the conductive layer and the insulating layer are cured at the preset temperature and the preset pressure, the obtained multilayer structure is cooled at a cooling rate not greater than the target cooling rate. The target time is the sum of an original curing time and a first preset time. The original curing time is determined based on the characteristics of the plate material, the conductive layer and the insulating layer. The value range of the first preset time is between 12 minutes and 18 minutes. The value range of the target cooling rate is between 0.8°C / minute and 1.2°C / minute.

[0011] According to a printed circuit board assembly provided by the present invention, the diameter of the first enlarged pad is the product of the diameter of the first ordinary pad and a target multiple; the diameter of the second enlarged pad is the product of the diameter of the second ordinary pad and a target multiple; the target multiple ranges from 1.1 to 1.3.

[0012] According to a printed circuit board assembly provided by the present invention, the storage modulus of the plate material is not less than a preset storage modulus; the preset storage modulus has a value range of 15000 MPa to 21000 MPa.

[0013] A printed circuit board assembly provided according to the present invention also includes: electronic components; the electronic components are connected to the pads by welding; during the process of welding the electronic components to the pads, the heating rate of the target printed circuit board is not greater than the target heating rate, the glass transition temperature range of the board is 150°C to 217°C, and the target heating rate ranges from 0.4°C / second to 0.6°C / second.

[0014] The present invention also provides an integrated circuit, comprising: any one of the printed circuit board assemblies described above.

[0015] The present invention also provides an electronic device, comprising: any integrated circuit as described above.

[0016] The printed circuit board assembly, integrated circuit and electronic device provided by the present invention, on the printed circuit board assembly, each soldering pad arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board is a first soldering pad or a second soldering pad, so that the thermal expansion coefficients of each soldering pad arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board are consistent, and the situation where the first soldering pad and the second soldering pad are adjacent to each other in the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board is avoided, thereby better avoiding the insulation layer under the soldering pads arranged at the boundary and corners of the solder ball array packaging area on the target printed circuit board from being torn, which can improve the stability of the electrical performance and mechanical strength of the printed circuit board assembly and can improve the reliability of the printed circuit board assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of a solder pad using VIPPO design and a solder pad not using VIPPO design in the related art.

[0019] Figure 2 is a schematic diagram of a printed circuit board assembly provided by the present invention.

[0020] Figure 3 It is a top view of a solder ball array packaging area on a target printed circuit board in a printed circuit board assembly provided by the present invention.

[0021] Figure 4 It is a local cross-sectional view of the boundary of the solder ball array packaging area on the target printed circuit board in the printed circuit board assembly provided by the present invention.

[0022] Figure 5 It is a cross-sectional view of a first enlarged solder pad disposed at a corner of a solder ball array packaging area of ​​a target printed circuit board in a printed circuit board assembly provided by the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the description of the present application, the terms "first", "second", etc. are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are usually a class, and the number of objects is not limited. For example, the first object can be one or more. In addition, in the description of the present application, "and / or" represents at least one of the connected objects, and the character " / " generally represents that the front and back associated objects are in an "or" relationship.

[0026] It should be noted that PCBA refers to a circuit board assembly formed by soldering electronic components to a PCB. PCBA is not only a carrier for the electrical connection of electronic components, but also a core component in electronic equipment, responsible for connecting, supporting and protecting electronic components, and providing functions such as electrical connection, signal transmission and power management. PCBA is widely used in various electronic equipment and product fields, including consumer electronics, home appliances, communication equipment, medical equipment, industrial automation equipment, automotive electronics, etc.

[0027] In the field of printed circuit board assembly, the pads on the PCB are the key part of the electrical connection between electronic components and the PCB. The welding quality and long-term reliability of the pads on the PCB are very important, especially for some fields that require high reliability of the board, such as automobiles, servers, storage, switches, and communications. Since the board needs to run for a long time, the welding quality and long-term reliability of the pads on the PCB are very high.

[0028] The insulating layer under the pad on the PCB has the weakest bonding force in the entire welding structure of the PCB, which means that the rigidity of the insulating layer under the pad on the PCB is the weakest. The pad on the PCB will be subjected to great stress during the welding process. If the stress is greater than the bonding force of the insulating layer under the pad, the insulating layer under the pad will tear.

[0029] Moreover, with the development of electronic information technology, the size of integrated circuits in related technologies has gradually increased, and the size of some integrated circuits has even reached 90*90mm. The larger the size of the integrated circuit, the more difficult it is to control the flatness of the integrated circuit itself to be very small. Accordingly, for integrated circuits with larger sizes, the flatness of the PCB board corresponding to the above integrated circuit is difficult to achieve the expected level, resulting in greater difficulty in soldering electronic components on the PCB board corresponding to the above integrated circuit, and prone to poor soldering problems such as empty soldering, pillow soldering, and short circuits.

[0030] The above-mentioned poor welding problem may cause welding cracks under stress, and welding cracks will cause the insulation layer in the PCBA to tear, especially at the edges and corners of the ball grid array (BGA) area on the PCB board. The solder joints at the above positions are subject to greater stress, so the above positions are more prone to welding cracks and then insulation layer tearing. Among them, the BGA area on the PCB board is usually determined according to the circuit design requirements and packaging specifications of the integrated circuit, and is used to achieve the interconnection between the integrated circuit and the PCB board.

[0031] In addition, due to the high integration of integrated circuits, the design density of the PCB boards corresponding to the integrated circuits is very high. In the related technology, the VIPPO (via in pad plated over) design can be used to improve the soldering density of the PCB board. In the VIPPO design, a via is made inside the pad, and a layer of metal is electroplated on the via to make it flush with the pad surface, and an insulating material is filled inside the electroplating layer, thereby allowing electronic components to be directly soldered above the via to improve the soldering density of the PCB board.

[0032] However, since the pads designed with VIPPO need to be punched, it will affect the routing of the inner layer of the PCB board, and thus affect the design density. Therefore, not all pads on the PCB board will adopt the VIPPO design. Figure 1 Schematic diagram of a pad using VIPPO design and a pad not using VIPPO design in the related art. Figure 1 shown.

[0033] like Figure 1As shown in the figure, the pads using VIPPO design are affected by the electroplating layer on the via wall below and the insulating material filled, resulting in different thermal expansion coefficients between pads using VIPPO design and pads not using VIPPO design. If pads using VIPPO design are adjacent to pads not using VIPPO design, then when electronic components are soldered on pads using VIPPO design and pads not using VIPPO design, the stresses on pads using VIPPO design and pads not using VIPPO design are different, which can easily cause the insulating layer under pads using VIPPO design to tear. The insulating layer under pads using VIPPO design is torn as shown in the figure. Figure 1 shown.

[0034] In this regard, the present invention provides a printed circuit board assembly, an integrated circuit and an electronic device. The printed circuit board assembly provided by the present invention can better avoid the tearing of the insulating layer under the pads at the boundaries and corners of the solder ball array packaging area on the printed circuit board, can improve the stability of the electrical performance and mechanical strength of the printed circuit board assembly, and can improve the reliability of the printed circuit board assembly.

[0035] Combine the following Figure 2-Figure 5 A printed circuit board assembly of the present invention is described.

[0036] Figure 2 Schematic diagram of the printed circuit board assembly provided by the present invention. Figure 2 As shown, the printed circuit board assembly 201 includes: a target printed circuit board 202 and a solder pad; the solder pad is arranged on the insulating layer in the target printed circuit board 202; The pad includes a first pad 203 and / or a second pad 204; a via is provided below the first pad 203, the inner wall of the via is covered with a metal layer, and the interior of the metal layer is filled with an insulating material; All the pads arranged along the circumference of the boundary of the solder ball array packaging area 205 on the target printed circuit board 202 are first pads 203 or second pads 204 .

[0037] It can be understood that the first pad 203 in the embodiment of the present invention is a pad designed with VIPPO, and the second pad 204 is a pad not designed with VIPPO.

[0038] It should be noted that the target printed circuit board 202 in the embodiment of the present invention is obtained by laminating the stacked plates, the conductive layer and the insulating layer using a target laminating method. The target laminating method is used to improve the storage modulus of the target printed circuit board 202 and / or improve the flatness of the target printed circuit board 202. The target laminating method is not specifically limited in the embodiment of the present invention.

[0039] It should be noted that the size, thickness, quantity, material properties and stacking order of the plate material, conductive layer and insulating layer in the target printed circuit board 202 in the embodiment of the present invention may be determined based on the design requirements of the target printed circuit board 202. The size, thickness, quantity, material properties and stacking order of the plate material, conductive layer and insulating layer in the target printed circuit board 202 are not specifically limited in the embodiment of the present invention.

[0040] It should be noted that the solder ball array packaging area on the target printed circuit board 202 in the embodiment of the present invention can be determined based on the design requirements of the target printed circuit board 202. The specific position of the solder ball array packaging area on the target printed circuit board 202 is not limited in the embodiment of the present invention.

[0041] It is understandable that, compared with the pads arranged at the middle position of the solder ball array package area on the target printed circuit board 202, the pads arranged at the border and corners of the solder ball array package area on the target printed circuit board 202 are subjected to greater stress during the welding process, so the insulating layer under the pads arranged at the border and corners of the solder ball array package area on the target printed circuit board 202 is more likely to tear. In addition, when the pads adopting the VIPPO design and the pads not adopting the VIPPO design are adjacent, it is more likely to cause the insulating layer under the pads adopting the VIPPO design to tear.

[0042] Figure 3 It is a top view of a solder ball array packaging area on a target printed circuit board in a printed circuit board assembly provided by the present invention. Figure 4 FIG. 1 is a partial cross-sectional view of the boundary of the solder ball array packaging area on the target printed circuit board in the printed circuit board assembly provided by the present invention. Figure 3 and Figure 4 As shown, on the printed circuit board assembly 201 in the embodiment of the present invention, all the solder pads arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board 202 are first solder pads 203 or second solder pads 204, so that the thermal expansion coefficients of the solder pads arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board 202 are consistent, avoiding the situation where the first solder pad 203 and the second solder pad 204 of the solder pads arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board 202 are adjacent, thereby better avoiding the insulation layer under the solder pads arranged at the boundary and corners of the solder ball array packaging area on the target printed circuit board 202 from being torn, which can improve the stability of the electrical performance and mechanical strength of the printed circuit board assembly 201 and improve the reliability of the printed circuit board assembly 201.

[0043] As an optional embodiment, the target printed circuit board 202 is obtained by laminating the plate material, the conductive layer and the insulating layer. When laminating the plate material, the conductive layer and the insulating layer, the curing time of the stacked plate material, the conductive layer and the insulating layer under the preset temperature and the preset pressure is the target time. The target time is the sum of the original curing time and the first preset time. The original curing time is determined based on the characteristics of the plate material, the conductive layer and the insulating layer. The value range of the first preset time is between 12 minutes and 18 minutes.

[0044] It should be noted that the lamination process is one of the key steps in manufacturing multi-layer printed circuit boards. The lamination process aims to tightly combine multiple boards, conductive layers (such as copper foil) and insulating layers (such as PP sheets or resins) together through high temperature and high pressure to form a multi-layer printed circuit board with complex electrical connections and insulation structures.

[0045] When the stacked plates, conductive layers and insulating layers are laminated by the target lamination method in the embodiment of the present invention, the plates, conductive layers and insulating layers to be stacked are first prepared based on the design requirements of the target printed circuit board 202, and then the plates are cleaned to remove dust, oil and other impurities on the surface to ensure the lamination quality, and the surface of the conductive layer is chemically treated to form metal oxide fluff, thereby increasing the surface roughness and adhesion of the conductive layer and improving the lamination bonding strength.

[0046] The processed plates, conductive layers and insulating layers are stacked according to the design requirements of the target printed circuit board 202, and the plates, conductive layers and insulating layers are precisely aligned using dedicated equipment or tools to obtain stacked plates, conductive layers and insulating layers.

[0047] The stacked plates, conductive layers and insulating layers are placed in a laminating machine, heated by a heating plate, a heating clamp or other heating elements, and high voltage is applied to the stacked plates, conductive layers and insulating layers.

[0048] When the stacked plates, conductive layers and insulating layers reach the preset temperature and the pressure applied to the stacked plates, conductive layers and insulating layers reaches the preset pressure, the temperature of the stacked plates, conductive layers and insulating layers are maintained at the preset temperature and the pressure applied to the stacked plates, conductive layers and insulating layers are maintained at the preset pressure within the target time, so that the stacked plates, conductive layers and insulating layers are cured at the preset temperature and preset pressure for the above-mentioned target time.

[0049] While maintaining the temperature of the stacked plates, conductive layers and insulating layers at a preset temperature and the pressure applied to the stacked plates, conductive layers and insulating layers at a preset pressure for a target time, the obtained multilayer structure can be cooled to obtain a stable target printed circuit board 202.

[0050] It should be noted that the preset temperature and the preset pressure in the embodiment of the present invention may be determined based on prior knowledge and / or actual conditions. The specific values ​​of the preset temperature and the preset pressure are not limited in the embodiment of the present invention.

[0051] Preferably, the value of the first preset duration in the embodiment of the present invention is 15 minutes.

[0052] In the lamination process of the target printed circuit board in the embodiment of the present invention, according to the characteristics of the plate materials, the curing time of the stacked plate materials, the conductive layer and the insulating layer at the preset temperature and the preset pressure is extended, so that the curing degree of the plate materials in the target printed circuit board can be improved, and then the storage modulus of the target printed circuit board obtained by lamination can be improved, and then the structural rigidity and thermomechanical stability of the target printed circuit board can be improved, and the pads arranged on the target printed circuit board can be better prevented from tearing the insulating layer under the pads during the welding process, which can further improve the electrical performance of the printed circuit board assembly and the stability of the mechanical strength, and can improve the reliability of the printed circuit board assembly.

[0053] As an optional embodiment, the target printed circuit board 202 is obtained by laminating the plate material, the conductive layer and the insulating layer. When laminating the plate material, the conductive layer and the insulating layer, the stacked plate material, the conductive layer and the insulating layer are cured at a preset temperature and a preset pressure, and then the obtained multilayer structure is cooled at a cooling rate not greater than the target cooling rate. The target cooling rate ranges from 0.8°C / minute to 1.2°C / minute.

[0054] It should be noted that when the target pressing method is used to press the stacked plates, conductive layers and insulating layers in the embodiment of the present invention, after the stacked plates, conductive layers and insulating layers are cured at a preset temperature and a preset pressure, the obtained multi-layer structure can be cooled, and the cooling rate of the above-mentioned multi-layer structure can be ensured to be no greater than the target cooling rate.

[0055] After the multi-layer structure is cooled, a stable target printed circuit board 202 can be obtained.

[0056] Preferably, the target cooling rate is 1°C / minute.

[0057] In the lamination process of the target printed circuit board in the embodiment of the present invention, after the stacked plates, conductive layers and insulating layers are cured at a preset temperature and a preset pressure, the stress inside the target printed circuit board can be more fully released by controlling the cooling rate of the multilayer structure obtained after curing, and the board bending and warping phenomena of the target printed circuit board can be improved, thereby improving the flatness of the target printed circuit board, and further, when soldering electronic components on the pads on the target printed circuit board, it is possible to better avoid welding defects such as empty soldering, pillow soldering, and short circuits, thereby better avoiding the tearing of the insulating layer under the soldering pad, and further improving the electrical performance of the printed circuit board assembly and the stability of the mechanical strength, and the reliability of the printed circuit board assembly.

[0058] As an optional embodiment, the storage modulus of the plate is not less than a preset storage modulus; the preset storage modulus ranges from 15000 MPa to 21000 MPa.

[0059] Preferably, the preset storage modulus value is 18000 MPa.

[0060] The target printed circuit board in the embodiment of the present invention, on the basis of meeting the signal requirements, selects a plate material with a storage modulus of not less than 18000 MPa at room temperature, which can improve the rigidity of the insulating layer in the target printed circuit board and better prevent the insulating layer located under the soldering pad on the target printed circuit board from being torn during the soldering process.

[0061] As an optional embodiment, the first pad 203 includes a first common pad and a first enlarged pad, and the diameter of the first enlarged pad is greater than the diameter of the first common pad; In the case where all the pads arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board 202 are first pads 203, the first pads 203 arranged at the corners of the solder ball array packaging area on the target printed circuit board 202 are first enlarged pads, and the remaining first pads 203 arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board 202 are first common pads, and the target area on the first enlarged pad arranged at the corners of the solder ball array packaging area on the target printed circuit board 202 is covered by solder resist 501, and the target annular area on the first enlarged pad is an area on the outside of the first enlarged pad that is larger than the first common pad; The second pad 204 includes a second common pad and a second enlarged pad, and the diameter of the second enlarged pad is greater than the diameter of the second common pad; In the case where all the pads arranged circumferentially along the boundary of the solder ball array packaging area on the target printed circuit board 202 are second pads 204, the second pads 204 arranged at the corners of the solder ball array packaging area on the target printed circuit board 202 are second enlarged pads, and the remaining second pads 204 arranged circumferentially along the boundary of the solder ball array packaging area on the target printed circuit board 202 are second common pads, and the target area on the second enlarged pad arranged at the corners of the solder ball array packaging area on the target printed circuit board 202 is covered by solder resist 501, and the target annular area on the second enlarged pad is an area on the outer side of the second enlarged pad that is larger than the second common pad.

[0062] It can be understood that the pads disposed at the corners of the solder ball array package area on the target printed circuit board 202 are subjected to the greatest stress during the soldering process. Therefore, in the printed circuit board assembly 201 in the embodiment of the present invention, when all the pads disposed circumferentially along the boundary of the solder ball array package area on the target printed circuit board 202 are first pads 203, the diameter of the first enlarged pad disposed at the corners of the solder ball array package area of ​​the target printed circuit board 202 is greater than the diameter of the first common pad disposed at other positions on the target printed circuit board 202, and the target annular area of ​​the first enlarged pad disposed at the corners of the solder ball array package area of ​​the target printed circuit board 202 is covered with solder resist 501, thereby ensuring that the exposed area of ​​the first enlarged pad disposed at the corners of the solder ball array package area of ​​the target printed circuit board 202 is equal to the area of ​​the first common pad disposed at other positions on the target printed circuit board 202.

[0063] Alternatively, in the printed circuit board assembly 201 in the embodiment of the present invention, when all the pads arranged circumferentially along the boundary of the solder ball array packaging area on the target printed circuit board 202 are second pads 204, the diameter of the second enlarged pad arranged at the corner of the solder ball array packaging area of ​​the target printed circuit board 202 is greater than the diameter of the second common pad arranged at other positions on the target printed circuit board 202, and the target annular area of ​​the second enlarged pad arranged at the corner of the solder ball array packaging area of ​​the target printed circuit board 202 is covered with solder resist 501, thereby ensuring that the exposed area of ​​the second enlarged pad arranged at the corner of the solder ball array packaging area of ​​the target printed circuit board 202 is equal to the area of ​​the second common pad arranged at other positions on the target printed circuit board 202.

[0064] Figure 5 2 is a cross-sectional view of a first enlarged pad disposed at a corner of a solder ball array packaging area of ​​a target printed circuit board in a printed circuit board assembly provided by the present invention. Figure 5 shown.

[0065] As an optional embodiment, the diameter of the first enlarged pad is the product of the diameter of the first ordinary pad and the target multiple; the diameter of the second enlarged pad is the product of the diameter of the second ordinary pad and the target multiple; the target multiple ranges from 1.1 to 1.3.

[0066] Preferably, the target multiple is 1.2.

[0067] The embodiment of the present invention covers the target area of ​​the pads arranged at the corners of the solder ball array packaging area of ​​the target printed circuit board with solder resist oil, and can use the solder resist oil to reinforce the pads arranged at the corners of the solder ball array packaging area of ​​the target printed circuit board, thereby reducing the stress on the insulating layer under the pads arranged at the corners of the solder ball array packaging area of ​​the target printed circuit board, and can better avoid the insulation layer from being torn under the pads arranged at the corners of the solder ball array packaging area on the target printed circuit board, and can further improve the electrical performance of the printed circuit board assembly and the stability of the mechanical strength, and can improve the reliability of the printed circuit board assembly.

[0068] As an optional embodiment, the target printed circuit board 202 is obtained by laminating the plate material, the conductive layer and the insulating layer. When laminating the plate material, the conductive layer and the insulating layer, the curing time of the stacked plate material, the conductive layer and the insulating layer at the preset temperature and the preset pressure is the target time. After the stacked plate material, the conductive layer and the insulating layer are cured at the preset temperature and the preset pressure, the obtained multilayer structure is cooled at a cooling rate not greater than the target cooling rate. The target time is the sum of the original curing time and the first preset time. The original curing time is determined based on the characteristics of the plate material, the conductive layer and the insulating layer. The value range of the first preset time is between 12 minutes and 18 minutes. The value range of the target cooling rate is between 0.8°C / minute and 1.2°C / minute.

[0069] When the stacked plates, conductive layers and insulating layers are laminated by the target lamination method in the embodiment of the present invention, the plates, conductive layers and insulating layers to be stacked are first prepared based on the design requirements of the target printed circuit board 202, and then the plates are cleaned to remove dust, oil and other impurities on the surface to ensure the lamination quality, and the surface of the conductive layer is chemically treated to form metal oxide fluff, thereby increasing the surface roughness and adhesion of the conductive layer and improving the lamination bonding strength.

[0070] The processed plates, conductive layers and insulating layers are stacked according to the design requirements of the target printed circuit board 202, and the plates, conductive layers and insulating layers are precisely aligned using dedicated equipment or tools to obtain stacked plates, conductive layers and insulating layers.

[0071] The stacked plates, conductive layers and insulating layers are placed in a laminating machine, heated by a heating plate, a heating clamp or other heating elements, and high voltage is applied to the stacked plates, conductive layers and insulating layers.

[0072] When the stacked plates, conductive layers and insulating layers reach the preset temperature and the pressure applied to the stacked plates, conductive layers and insulating layers reaches the preset pressure, the temperature of the stacked plates, conductive layers and insulating layers are maintained at the preset temperature and the pressure applied to the stacked plates, conductive layers and insulating layers are maintained at the preset pressure within the target time, so that the stacked plates, conductive layers and insulating layers are cured at the preset temperature and preset pressure for the above-mentioned target time.

[0073] While maintaining the temperature of the stacked plates, conductive layer and insulating layer at a preset temperature and the pressure applied to the stacked plates, conductive layer and insulating layer at a preset pressure for a target time, the obtained multi-layer structure can be cooled and the cooling rate of the multi-layer structure can be ensured to be no greater than the target cooling rate.

[0074] After the multi-layer structure is cooled, a stable target printed circuit board 202 can be obtained.

[0075] Preferably, the first preset time length in the embodiment of the present invention is 15 minutes; the target cooling rate is 1°C / minute.

[0076] In the lamination process of the target printed circuit board in the embodiment of the present invention, according to the characteristics of the plate materials, the curing time of the stacked plate materials, the conductive layer and the insulating layer at the preset temperature and the preset pressure is extended, so that the curing degree of the plate materials in the target printed circuit board can be improved, and then the storage modulus of the target printed circuit board obtained by lamination can be improved, and then the structural rigidity and thermomechanical stability of the target printed circuit board can be improved, and the pads set on the target printed circuit board can be better prevented from tearing the insulating layer under the pads during the welding process. After the stacked plate materials, the conductive layer and the insulating layer are cured at the preset temperature and the preset pressure, the cooling rate of the multilayer structure obtained after curing can be controlled, so that the stress inside the target printed circuit board can be more fully released, the board bending and board warping of the target printed circuit board can be improved, and then the flatness of the target printed circuit board can be improved, and then when the electronic components are soldered on the pads on the target printed circuit board, the occurrence of poor welding problems such as empty welding, pillow welding, and short circuit can be better avoided, so as to better avoid the tearing of the insulating layer under the pads, and the electrical performance and mechanical strength stability of the printed circuit board assembly can be further improved, and the reliability of the printed circuit board assembly can be improved.

[0077] As an optional embodiment, the printed circuit assembly also includes: electronic components; the electronic components are connected to the pads by welding; during the process of welding the electronic components to the pads, the heating rate of the target printed circuit board 202 is not greater than the target heating rate, the glass transition temperature range of the board is 150°C to 217°C, and the target heating rate ranges from 0.4°C / second to 0.6°C / second.

[0078] Preferably, the target heating rate is 0.5°C / second.

[0079] In the printed circuit assembly of the embodiment of the present invention, during the process of soldering electronic components to the pads on the target printed circuit board 202, the glass transition temperature range of the middle plate material of the target printed circuit board 202 in the heating stage is 150°C to 217°C, and the heating rate of the target printed circuit board 202 is no more than 0.5°C / second, which can reduce the stress generated during the process of soldering electronic components to the pads on the target printed circuit board 202, thereby reducing the deformation of the target printed circuit board and reducing the risk of tearing of the insulating layer under the pads.

[0080] It should be noted that in the related art, a red ink dyeing test can be used to test whether the insulation layer of the printed circuit board assembly 201 is torn.

[0081] The specific steps of the red ink staining test include: blowing the integrated circuit to be subjected to the red ink staining test clean, placing it in a red ink container, vacuuming for one hour, taking it out and baking it for 12 hours, then polishing the surface of the integrated circuit for easy bonding, and then gluing it with magic glue, leaving it for six hours, pulling the integrated circuit off with force, and then observing the chip side of the integrated circuit and the printed circuit board assembly 201 side for red ink infiltration and staining, and taking pictures. Based on the red ink infiltration and staining of the integrated circuit, it can be determined whether the insulation layer in the printed circuit board assembly 201 corresponding to the integrated circuit is torn.

[0082] The red ink dyeing test proves that the printed circuit board assembly 201 provided by the present invention can better prevent the insulation layer from being torn under the pads at the border and corners of the solder ball array packaging area on the target printed circuit board 202 .

[0083] The printed circuit board assembly provided by the present invention solves the technical problem that the insulating layer under the pad is easy to tear for boards and cards that need to be operated for a long time in the fields of automobiles, servers, storage, switches and communications, especially for some boards and cards containing large-size integrated circuits. Since the larger the integrated circuit is, the more difficult it is to control the flatness of the integrated circuit itself, the more difficult it is to control the flatness of the solder ball array packaging area on the printed circuit board corresponding to the integrated circuit, and the more difficult it is to control the deformation during high-temperature welding, resulting in the technical problem that welding cracks are more likely to occur at the edges and corners of the solder ball array packaging area on the printed circuit board, and then the insulating layer tears. The printed circuit board assembly provided by the present invention provides a set of full-process solutions from circuit board design to reflow soldering for such boards and cards, improves the long-term reliability of such boards and cards, and promotes the development of printed circuit board design, production and assembly technology.

[0084] Based on the contents of the above embodiments, an integrated circuit includes: any one of the above printed circuit board assemblies 201.

[0085] The integrated circuit in the embodiment of the present invention includes the above-mentioned printed circuit board assembly 201. The specific structure of the above-mentioned printed circuit board assembly 201 can refer to the contents of the above-mentioned embodiments, and will not be repeated in the embodiment of the present invention.

[0086] The integrated circuit in the embodiment of the present invention includes the printed circuit board assembly as described above. Based on the performance of the printed circuit board assembly being able to better avoid the tearing of the insulating layer under the pads at the boundaries and corners of the solder ball array packaging area arranged on the target printed circuit board, the electrical performance and mechanical strength stability of the integrated circuit can be improved, and the reliability of the integrated circuit can be improved.

[0087] Based on the contents of the above embodiments, an electronic device includes: the integrated circuit as described above.

[0088] The electronic device in the embodiment of the present invention includes the integrated circuit as described above, and the above integrated circuit includes the above printed circuit board assembly. Based on the performance of the above printed circuit board assembly in better avoiding the tearing of the insulating layer under the pads at the boundaries and corners of the solder ball array packaging area arranged on the target printed circuit board, the reliability of the electronic device can be improved.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A printed circuit board assembly, It is characterized in that include: A target printed circuit board and a pad; the pad is arranged on an insulating layer in the target printed circuit board; The pad includes a first pad and / or a second pad; a via is provided below the first pad, an inner wall of the via is covered with a metal layer, and an interior of the metal layer is filled with an insulating material; All the pads arranged along the circumference of the boundary of the solder ball array packaging area on the target printed circuit board are the first pads or the second pads.

2. The printed circuit board assembly according to claim 1, It is characterized in that The target printed circuit board is obtained by laminating the plate material, the conductive layer and the insulating layer. When the plate material, the conductive layer and the insulating layer are laminarized, the curing time of the stacked plate material, the conductive layer and the insulating layer under a preset temperature and a preset pressure is the target time. The target time is the sum of the original curing time and the first preset time. The original curing time is determined based on the characteristics of the plate material, the conductive layer and the insulating layer. The value range of the first preset time is between 12 minutes and 18 minutes.

3. The printed circuit board assembly according to claim 1, It is characterized in that The target printed circuit board is obtained by laminating a plate material, a conductive layer and an insulating layer. When the plate material, the conductive layer and the insulating layer are laminated, the stacked plate material, the conductive layer and the insulating layer are cured at a preset temperature and a preset pressure, and then the obtained multilayer structure is cooled at a cooling rate not greater than a target cooling rate. The target cooling rate ranges from 0.8°C / minute to 1.2°C / minute.

4. The printed circuit board assembly according to claim 1, It is characterized in that The first pad includes a first common pad and a first enlarged pad, and the diameter of the first enlarged pad is greater than the diameter of the first common pad; In the case where all the pads arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board are the first pads, the first pads arranged at the corners of the solder ball array packaging area on the target printed circuit board are the first enlarged pads, the remaining first pads arranged along the circumferential direction of the boundary of the solder ball array packaging area on the target printed circuit board are the first common pads, and the target area on the first enlarged pads arranged at the corners of the solder ball array packaging area on the target printed circuit board is covered by solder resist oil, and the target annular area on the first enlarged pad is an area on the outside of the first enlarged pad that is larger than the first common pad; The second pad includes a second common pad and a second enlarged pad, and the diameter of the second enlarged pad is greater than the diameter of the second common pad; In the case where all the pads arranged circumferentially along the boundary of the solder ball array packaging area on the target printed circuit board are the second pads, the second pads arranged at the corners of the solder ball array packaging area on the target printed circuit board are the second enlarged pads, the remaining second pads arranged circumferentially along the boundary of the solder ball array packaging area on the target printed circuit board are the second common pads, and the target area on the second enlarged pads arranged at the corners of the solder ball array packaging area on the target printed circuit board is covered by solder resist, and the target annular area on the second enlarged pad is an area on the outer side of the second enlarged pad that is larger than the second common pad.

5. The printed circuit board assembly according to claim 1, It is characterized in that The target printed circuit board is obtained by laminating the plate material, the conductive layer and the insulating layer. When laminating the plate material, the conductive layer and the insulating layer, the curing time of the stacked plate material, the conductive layer and the insulating layer at a preset temperature and a preset pressure is the target time. After the stacked plate material, the conductive layer and the insulating layer are cured at the preset temperature and the preset pressure, the obtained multilayer structure is cooled at a cooling rate not greater than the target cooling rate. The target time is the sum of the original curing time and the first preset time. The original curing time is determined based on the characteristics of the plate material, the conductive layer and the insulating layer. The value range of the first preset time is between 12 minutes and 18 minutes. The value range of the target cooling rate is between 0.8°C / minute and 1.2°C / minute.

6. The printed circuit board assembly according to claim 4, It is characterized in that The diameter of the first enlarged pad is the product of the diameter of the first ordinary pad and the target multiple; the diameter of the second enlarged pad is the product of the diameter of the second ordinary pad and the target multiple; the target multiple ranges from 1.1 to 1.

3.

7. The printed circuit board assembly according to claim 2, It is characterized in that The storage modulus of the plate is not less than a preset storage modulus; the preset storage modulus has a value range of 15000 MPa to 21000 MPa.

8. A printed circuit assembly according to claim 2, 3 or 5, It is characterized in that Also includes: Electronic components; the electronic components are connected to the pads by welding; during the process of welding the electronic components to the pads, the heating rate of the target printed circuit board is not greater than the target heating rate, the glass transition temperature range of the board is 150°C to 217°C, and the target heating rate ranges from 0.4°C / second to 0.6°C / second.

9. An integrated circuit, It is characterized in that include: A printed circuit board assembly as claimed in any one of claims 1 to 7.

10. An electronic device, It is characterized in that include: An integrated circuit as claimed in claim 9.

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